svn commit: r357004 - in head/sys: kern sys
Hans Petter Selasky
hps at selasky.org
Thu Jan 23 08:36:59 UTC 2020
On 2020-01-23 02:24, Gleb Smirnoff wrote:
> Author: glebius
> Date: Thu Jan 23 01:24:47 2020
> New Revision: 357004
> URL: https://svnweb.freebsd.org/changeset/base/357004
>
> Log:
> Enter the network epoch for interrupt handlers of INTR_TYPE_NET.
>
> Provide tunable to limit how many times handlers may be executed
> without reentering epoch.
>
> Differential Revision: https://reviews.freebsd.org/D23242
>
> Modified:
> head/sys/kern/kern_intr.c
> head/sys/sys/interrupt.h
>
> Modified: head/sys/kern/kern_intr.c
> ==============================================================================
> --- head/sys/kern/kern_intr.c Thu Jan 23 01:20:59 2020 (r357003)
> +++ head/sys/kern/kern_intr.c Thu Jan 23 01:24:47 2020 (r357004)
> @@ -48,6 +48,7 @@ __FBSDID("$FreeBSD$");
> #include <sys/mutex.h>
> #include <sys/priv.h>
> #include <sys/proc.h>
> +#include <sys/epoch.h>
> #include <sys/random.h>
> #include <sys/resourcevar.h>
> #include <sys/sched.h>
> @@ -94,6 +95,9 @@ static int intr_storm_threshold = 0;
> SYSCTL_INT(_hw, OID_AUTO, intr_storm_threshold, CTLFLAG_RWTUN,
> &intr_storm_threshold, 0,
> "Number of consecutive interrupts before storm protection is enabled");
> +static int intr_epoch_batch = 1000;
> +SYSCTL_INT(_hw, OID_AUTO, intr_epoch_batch, CTLFLAG_RWTUN, &intr_epoch_batch,
> + 0, "Maximum interrupt handler executions without re-entering epoch(9)");
> static TAILQ_HEAD(, intr_event) event_list =
> TAILQ_HEAD_INITIALIZER(event_list);
> static struct mtx event_lock;
> @@ -587,6 +591,8 @@ intr_event_add_handler(struct intr_event *ie, const ch
> ih->ih_flags |= IH_MPSAFE;
> if (flags & INTR_ENTROPY)
> ih->ih_flags |= IH_ENTROPY;
> + if (flags & INTR_TYPE_NET)
> + ih->ih_flags |= IH_NET;
>
> /* We can only have one exclusive handler in a event. */
> mtx_lock(&ie->ie_lock);
> @@ -1196,11 +1202,12 @@ ithread_execute_handlers(struct proc *p, struct intr_e
> static void
> ithread_loop(void *arg)
> {
> + struct epoch_tracker et;
> struct intr_thread *ithd;
> struct intr_event *ie;
> struct thread *td;
> struct proc *p;
> - int wake;
> + int wake, epoch_count;
>
> td = curthread;
> p = td->td_proc;
> @@ -1235,8 +1242,21 @@ ithread_loop(void *arg)
> * that the load of ih_need in ithread_execute_handlers()
> * is ordered after the load of it_need here.
> */
> - while (atomic_cmpset_acq_int(&ithd->it_need, 1, 0) != 0)
> + if (ie->ie_hflags & IH_NET) {
> + epoch_count = 0;
> + NET_EPOCH_ENTER(et);
> + }
> + while (atomic_cmpset_acq_int(&ithd->it_need, 1, 0) != 0) {
> ithread_execute_handlers(p, ie);
> + if ((ie->ie_hflags & IH_NET) &&
> + ++epoch_count >= intr_epoch_batch) {
> + NET_EPOCH_EXIT(et);
> + epoch_count = 0;
> + NET_EPOCH_ENTER(et);
> + }
> + }
> + if (ie->ie_hflags & IH_NET)
> + NET_EPOCH_EXIT(et);
> WITNESS_WARN(WARN_PANIC, NULL, "suspending ithread");
> mtx_assert(&Giant, MA_NOTOWNED);
>
Beware that iflib uses GROUP TASKs to invoke the RX-path for packet
processing and only register a fast IRQ handler.
--HPS
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